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You're not a kid anymore. Maybe you're not exactly an adult woman yet, but you know that your body changes when you're a teen -- and you're so ready to move on.

On the other hand, all these changes can completely stress you out. You may worry that you’re not getting breasts as soon as the other girls. Or that you got your period way before everyone else, and OMG, what if that pad falls out of my bag?

As all this is happening, remember three important things:

It’s happening to everyone else, too. They might not talk about it, but even the most popular girls in school stress out over where to hide their tampons or if their antiperspirant is strong enough. (Really. They do.)

It’s normal.

You can survive it -- with a little help.

There are a few things about the big P -- puberty -- that happen to every girl, and that every girl has questions about.

1. Your Period

This is the biggie every girl wonders about. When will I get it? Am I the first one? Am I the last one? What if I get it in the middle of class and I bleed right through my pants and everyone sees?

“Girls wonder how to handle their period at school -- that’s one of the biggest things,” says Elizabeth Alderman, MD, professor of clinical pediatrics at the Albert Einstein School of Medicine in New York and an expert in issues affecting adolescent girls. “I tell them that there are some ways that you can predict when you’re likely to get your first period, and there are things you can do to prepare.”

Doctors measure the beginning of puberty using something called the Tanner scale, which looks at how much pubic hair you have and how much your breasts have developed. If you don’t have any pubic hair yet, or just a little peach fuzz, and your breasts are still mostly flat, you probably have some time before getting your period. But once you start to see coarser, curlier hair down there, and your breasts start to poke out a little, then odds are good that your period will soon follow.

So be prepared:

Carry a sanitary napkin in your purse, in a zippered makeup case so that if it falls out, nobody will see anything embarrassing.

If you wipe in the morning and you see anything brown, pink, or just something that looks a little different, wear a pad or at least a liner just in case. And wear dark-colored bottoms!

If you’re caught without a pad, remember it’s not going to be a huge gush of blood. Wad up some tissue until you can run to the nurse’s office for supplies.

If you get cramps in class, tell the teacher you have a headache and ask to go to the nurse’s office. “Tell the nurse the truth, of course, but you don’t have to announce to the whole class that you have menstrual cramps,” Alderman says.

2. Breasts

“During puberty, even the skinniest of girls develop more body fat,” Alderman says. “You go from straight board to hips, breasts, and all that. It can be pretty upsetting, but then it can be even more upsetting if it’s not happening to you when it’s happening to all the others.”

Despite what you may have heard, you can’t make your breasts grow faster, and you can’t slow down your body’s development either. All you can do is remember that everyone evens out in the end.

“If you’re an early developer, soon the others will catch up and wonder what all the fuss is about,” says Lynda Madaras, author of My Body, My Self for Girls. She taught puberty education in California for more than 20 years. “If you’re slow to develop -- well, you don’t see a lot of adults walking around who haven’t been through puberty. We all have our own timetable. It happens when it happens.”

3. Body Odor

It’s not like you’ve never sweated before, but did it always stinkso much? Nope.

Teenage sweat is different from kids’ sweat. You sweat more, and it smells different, because, with your hormones in overdrive, the glands in your armpits are getting a lot more active. The sweat they put out combines with bacteria to emit a smell that’s not exactly sweet perfume.

Use a deodorant or antiperspirant. What’s the difference? Deodorants cover up yucky smells; antiperspirants block sweating. “There are plenty of cute ones for girls,” says Alderman. “But some girls may need to use a stronger antiperspirant, like one for boys or men. There are also prescription antiperspirants if you really perspire a lot.

Wear 100% cotton underwear and clothing -- it “breathes” more and leaves you less drenched.

4. Facial and Body Hair

Hair in unwanted places is a common side effect of puberty. “Body odor and excess body hair often tend to go together,” says Alderman. “Girls get hairy arms or hairy upper lips, and it can be embarrassing.”

You can do certain things to help minimize the appearance of your body hair. “If a girl is younger, I’d recommend cosmetic things like waxing, depilatories, or bleaching,” Alderman says.

You can also shave your legs, underarm area, and bikini line, but don’t shave your face -- that’s just for guys.

If you have a lot of unwanted hair, irregular periods, and bad acne, and also struggle with your weight, you might have a condition called polycystic ovary syndrome (PCOS). If these things are happening to you, your doctor may check you for PCOS. If you have it, there are medications that can help with the hair and other symptoms.

5. Acne

Boys tend to get worse acne than girls, because their skin makes more oil, but that doesn’t mean you’ll be spared. Almost everyone gets acne at some point during their teen years.

With acne, as with sweat, it’s bacteria that are causing the problem. So for most mild to moderate cases of acne, you can keep it under control by:

Washing gently twice a day with a cleanser that’s specifically for the face. Scrubbing your face can worsen acne and irritate the skin.

Using makeup with the label “non-comedogenic.” That means it doesn’t clog the pores, which can aggravate acne

Not avoiding sunscreen. It’s a myth that baking in the sun will dry out your acne (it’ll just put you at risk for skin cancer), and there are plenty of non-comedogenic sunscreens that don’t clog your pores.

Talk About It

Through all of these changes, what you really need is someone to talk to. Yeah, bringing up your period to mom might seem like as much fun as walking through school with a giant zit on your nose, but you might be surprised how much she’ll understand.

“To get past the embarrassment factor, one thing you can do is bring it up in the car,” Madaras says. “It’s much easier because you don’t have to look at each other. And try introducing the subject by asking about their experiences first, rather than plunging into yours: ‘When you were my age, were you nervous about getting your period? Did Grandma ever talk to you about using deodorant?'"

If your parents are totally useless, or you're not comfortable going there with your Mom, that doesn't mean there's no one you can talk to. Try a favorite teacher, your aunt, a cool guidance counselor, or maybe your best friend's mom.

Madaras also recommends thinking about strategies for how you’ll manage the embarrassing stuff ahead of time. What if the hot guy from chemistry class sees you buying a box of sanitary pads? What if you realize you’re sweating up a storm after gym class and you don’t have any deodorant? “What would you do if that happened? How would you survive the experience?” Madaras asks. “It’s easier to handle things if you aren’t taken by surprise.”

Remember, all your friends are worrying and wondering about these things, too. “I get letters and e-mails all the time from girls asking if the size of their nipples is normal, if their period is normal, if their pubic hair is normal,” Madaras says. "And you know what? Almost every single time, it is.”